BLAKE SHELTON’s ex-wife — who helped launch him to stardom before he allegedly cheated on her with MIRANDA LAMBERT — is now barely scraping by as an elementary schoolteacher in Kansas.

And as if marrying Miranda wasn’t painful enough for his ex-wife and former road manager Kaynette Williams, the country crooner is now taking cheap shots at her in interviews.

“Kaynette was not only a loyal wife, she stood by Blake through the roughest of times while he was struggling,” a family friend told The ENQUIRER. “But Blake turned his back on her for Miranda.

“Without Kaynette to keep his career on track, it’s unlikely he would have ever reached his level of stardom.”

In a recent interview, Blake slammed his divorce to Kaynette, calling it “the worst experience of my life.” He added that he didn’t rush back into marriage because “nothing was worth risking that again.”

Blake courted Kaynette for several years before they married in 2003. When he filed for divorce in February 2006, he and Miranda had already known each other for nearly six months.

In divorce papers, Kaynette claimed Blake was “guilty of inappropriate marital conduct.”

The ENQUIRER recently found Kaynette living in a secluded, modest home on the outskirts of Great Bend, Kan.

Pick up this week's issue — on newsstands now — to find out what Kaynette told The ENQUIRER in an exclusive interview!